Nitrocellulose lacquer



Patented Dec. 20, 1927.

UNITED STATES PATENT GFFICE.

IRVIN W. HUMPHREY, OF WHARTON, NEW JERSEY, ASSIGNOR TO HERCULES POWDER COMPANY, OF WILMINGTON, DELAWARE, ACORPORA'IION OF DELAWARE.

NITROCELLULOSE LACQ'UER.

No Drawing.

The object of my invention is to provide a. nitrocellulose lacquer or varnish. Another object of my invention is to provide 2. nitrocellulose lacquer containing an ingredient 6 which will serve to some extent as a substitute for castor oil and other substances which are used to produce films of high flexibility. Another object of the invention is to produce a nitrocellulose lacquer in- 10 gredient whichmay'be used as a substitute,

in whole or in part, for amyl or butyl acetates and which can be produced more cheaply,'thereby effecting asaving in the cost of manufacturing the lacquer.

Pine oil is known to be a complex mixture of different substances, including terpineol, methyl chavicol, borneol, fenchyl alcohol, terpene hydrocarbons and smaller amounts of several other bodies. Pine oil itself has no colloiding action upon nitrocotton, and its individual constituents also possess little colloiding power. However, certain of these constitutents, notably borneol and fenchyl alcohol, yield, on oxidation, the

ketones camphor and fenchone respectively, the former being a well known colloiding agent for nitrocellulose.

Pine oil contains about five per cent of borneol, and approximately as much fenchyl 0 alcohol. These two alcohols cannot be easily isolated from pine oil in a high degree of purity by means of fractionation because of the nearness of their boiling points with those of some of the other constituents of pine oil.

As set forth in patent applications filed by me November 22, 1924, Serial No. 7 51,682, and August 17 1925, Serial No. 50,839, of the latter of which this a plication is a con- 40 tinuation in part, it has een found feasible to treat pine oil with certainoxidizing agents and obtain a liquid, which may be designated oxidized pine oil, which exhibits considerable colloidin action on nitrocellulose. When pine. 01 is oxidized under proper conditions, it may contain approximately ten per cent of theketones camphor and fenchone and, in addition, small amounts of other oxidized substances which colloid nitrocellulose.

the pine oil is oxidized to inert bodies,

but

. the operation may be so conducted that a Application filed July 23,

Another portion of 1926. Serial No. 124,549.

great portion of the pine oil remains unaltered, servingas a diluent to the active colloiding agentsbut possessing a strong solvent power for resins.

A solution of nitrocellulose ma be prepared in straight oxidized ine oil, but on account of the rather high oiling range of oxidized pine oil, which is comparable to that of pine oil itself, it is usually desirable to add large proportions of lower boiling liquids. The latter may be either solvents or non-solvents for 1 nitrocellulose. Examples of solvents are acetone and butyl acetate, and of non-solvents, alcohol and benzene. It is possible to incorporate alarge proportion of a non-solvent in the vehicle without precipitating the nitrocellulose. Alcohol, even if it contains as much as five per cent of water, is found to be a desirable diluent from the standpoint of increasing the colloiding action of oxidized pine 011. Even if as much as several volumes of alcohol are added, the colloiding action of oxidized pine oil is accelerated to a remarkable degree.

Several oxidizing agents have been employed. in preparing oxidized pine oil. Nitric acid is well adapted for use on a fraction of pine oil that is rich in fenchyl alco hol. Sodium or potassium bichromate, or chromic acid, is preferable in some respects to nitric'acid, since the latter converts much of the pine oil into undesired products. I have employed other oxidizing agentssuch as chlorine, potassium permanganate and sodium hypochlorite, as well.

According to one method of oxidizing pine oil, as described in both of said prior atent applications, the pine oil is treated w1th 4.2

times its weight of an oxidizing mixture consisting of 15% sodium bichromate, 20% of sulfuric acid of 66 B. and 65% of water,

but different proportions of the oxidizing The crude it is also stated that treating oxidized pine oil with a suit-able dehydrator results in the conversion of a large part (say 60 per cent) of the oxidized pine oil into a lower boiling product, which, if desired, may be distilled off, leaving a residue comprising about 35 per cent of the original. pine oil. As a typical example, it is stated that pine 011,- oxidized as described, is heated for one and one-half hours to 150 C. with two per cent of fullers earth. The fullers earth is then separated from the liquid. and the latter is distilled and collected in one lot. The product may be designated type A. It may be used in lacquers in much the same manner as any other oxidized pine oil, being blended with non-solvent diluents and permissibly with other nitrocellulose solvents.

The advantages of .type over simple oxidized pine oil are:

1) Greater volatility.

t2) Better solvent action on nitrocellulose in certain solvent mixtures.

(3) Greater freedom from blushing 1n lacquers.

It is, however, a poorer solvent for certain resins than straight oxidized pine oil.

The following is a comparison of the boiling ranges of typical samples of simple 0x1- dized pine oil and type A- Oxidized pine oil A H b. 0. t 186 176 25g, :351:17--- 198 180 50 0 over at--. 208 186 over at--. 210 190 00%over at 215 210 They differ chemically chiefly in the fact that part or all of the alpha-terpineol (b. p. 218 C.) in oxidized pine oil is converted into lower boiling substances (b. p. 170-185 0.) when typeA is prepared.

These lower boiling substances consist largely of terpene hydrocarbons, dipentene and others. The alpha-terpineol which is present in oxidizedpine oil has little colloiding action on nitrocellulose. The active colloiding ingredients in oxidized ine oil (camphor, fenchone, etc.) are not in ured if the dehydration treatment be properly ap-' the manner set forth in my earlier application and as hereinbefore described or in any other eflicient way.

(d) The oxidized residual refined by steam distillation.

(e) The refined oxidized residual pine oil may be then added to part or all of the distillate ffom step (-6), thereby obtainlng the pine oil is then product hereinbefore designated as type A.

having a boiling range approximating that hereinbefore specified for type A.

However, the oxidized residual pine oil resulting from step (a) may be employed off through a fractionating column. The

residue is then oxidized as hereinbefore described. The crude product is refined by steam distillation and is then blended with the first distillate.

Any reagent whose chief effect is that of splitting oif chemically combined water from certain of the pine oil constituents, notably terpineol, may .be used as a dehydrating agent. While a wide variety of dehydrators may be employed, it is preferable to use one which decomposes the terpineol without attacking the other constituents. Mineral acids, e. g. dilute sulfuric acid, acid salts (e. g. sodium bisulfate), saltswhich give an acid reaction on hydrolysis (e. g. copper sulfate), small amounts of iodin or bromin, or various substances which dehydrate by virtue of surface catalysis, may be employed.

The latter class includes activated carbon, fullers earth, kieselguhr, and in some instances other argillaceous or silioious earths.

In place of starting with pine oil as the raw material, I may nsethe by-product oil that is obtained in preparing terpin hydrate from pine oil.

The oxidized and dehydrated pine oil products resulting from the foregoing processes which comprise (in the order stated or the reverse order) partial oxidation of oxidizable constituents of pine oil and dehydration to convert such constituents into a lower boiling product have, except for their lesser capacity to dissolve certain resins, all the advantages of oxidized pine oil products produced by simple oxidation of their oxidizable constituents, and in addition have the advantages, hereinbefore mentioned, of greater volatility, better solvent action on nitrocellulose in certain solvent mixtures, andgreater freedom from blushingin lacquers;

and are therefore preferred by many users.

Type A, like straight oxidized pine oil,

W111. contain a proportion of oxidized inert bodies, serving as diluents, and in preparing the nitrocellulose solution, it is usually desirable, as when using straight oxidized pine oil, to add rather large proportions of lower boiling liquids, which may be solvents or non-solvents for nitrocellulose.

The invention forming the subject-matter of this application does not comprehend a nitrocellulose lacquer with oxidized pine oil, broadly, since the same forms the subject matter of. the earlier of the hereinbefore specified prior patent applications, but is intended to comprehend any nitrocellulose lacquer comprising a solution of nitrocellulose with dehydrated and oxidized pine oil (the preponderating proportion of whose constituents have, preferably, a boiling range of 17 5220) and also such a solution with a diluent having a substantially lower boiling range than the boiling range of oxidized pine oil. More specifically, the present invention is intended to comprehend compositions like the following typical composition, which is submitted as a specific illustration or. preferred embodiment of, the broad invention:

Ingredients. Percentage. Low viscosity nitrocotton"; 10.5 Denatured alcohol 4.5 Benzene 26 Butanol 5 Ethyl acetate 6 Butyl acetate 16.5 Gum solution 16.5 Diethyl phthalate 5- Dehydrated and oxidized pine oil 10 Dehydrated and oxidized pine oil is intended to include pine oil certain of whose oxidizing constituents are oxidized even though some of its constituents may not be oxidized or oxidizable.

Substantially all the advantages of the advantage.

foregoing specific composition may be at-- tained with other compositions containing 1- of dehydrated and oxidized pine oil,

520% of low viscosity nitrocotton, 10-30% I of aliphatic alcohols, 530% of esters, 1 050% of aromatic hydrocarbons, and 520% of gum solutions (preferably about 5 0% gum), and approximately 5% of plasticizer.

Where reference is made to a nitrocellulose lacquer, I do not mean to include only those lacquers which contain resins, as the oxidized product is also applicable as a nitrocellulose solvent when resins are not present in the solution, and in fact, in the latter case, the product embodying my invention is of special Having now fully described my invention, what I claim and desire to protect by Letters Patent is: I

1. A nitrocellulose lacquer including a solution of nitrocellulose and containing dehydrated and oxidized pineoil constituents.

2. A nitrocellulose lacquer including a solution of nitrocellulose and dehydrated and oxidized pine oil constituents, and'one or more diluents having a substantially lower boiling range than the boiling range of oxidized pine'oil.

3. A nitrocellulose lacquer comprising a 

